1. Field of the Invention
The present invention relates to a battery module composed by stacking a plurality of stacked cells packaged in a metal composite film.
2. Description of the Related Art
In recent years, electric vehicles which use electricity as a power source and hybrid cars which run by a combination of an engine and a motor have attracted attention under the environment where air pollution due to exhaust gas from automobiles has been a global problem. In this connection, development of a high-power battery to be mounted on these types of vehicles, which achieves high energy/power densities, has occupied an important position in the industry.
For this type of high-power battery, for example, there is a lithium ion battery. As the lithium ion battery, a stacked cell has been known. In the stacked cell, planar positive and negative electrode plates are stacked with one another by interposing separators therebetween (refer to Japanese Patent Laid-Open Publication No. 9-50821 (published in 1997)).
In this stacked cell, both surfaces of a power generation element formed flat and rectangular are sandwiched by a pair of laminate sheets which are formed as polymer-metal composite films, and peripheral portions of the laminate sheets are joined by fusion, thus hermetically sealing an electrolyte solution as well as the power generation element.
The plurality of single stacked cells thus configured or a plurality of cell units into which the plurality of stacked cells thus formed are coupled together are stacked, and thus a battery module can be configured to be provided as a high-power battery.